The table shows the current status of the 4545 Team, LoneWolf and Chess960 leagues. In the future, I plan to extend this to cover some community leagues too (like Series, Rapid Battle and Infinite Quest). Check out the Lichess4545 overview to learn about all the leagues and initiatives run by the community.
status - ‘pre’ means pre-season, ‘mid’ means mid-season, and ‘post’ means postseason (which may indicate that all games have been played but the final standings haven’t been confirmed yet).
active - ‘FALSE’ means the current season is over but registrations for the next season aren’t open yet.
regs_open - shows whether the league is currently accepting registrations. Note that for the 4545 league, if a season has started, then new registrants can only sign up to play as an alternate (since the teams for the season have already been made).